PTL 1 discloses configuration of a cap mounted to a beverage bottle. To suppress deformation of bottle in factories, such a cap is generally mounted to a mouth of a bottle while a support ring provided in the mouth of the bottle is supported by a support piece.
In addition, delaminatable containers are known that inhibit entrance of air inside the container by an inner layer delaminated from an outer layer to be shrunk with a decrease in the contents (e.g., PTLs 2 to 3). Such a delaminatable container is provided with an inner bag composed of an inner layer and an outer shell composed of an outer layer. The delaminatable container is generally used by mounting a cap with a check valve to a mouth of a container body.
Such a container body is generally manufactured by blow molding using a tubular laminated parison. The container body has the bottom provided with a sealing portion formed by welding an end of the laminated parison. Since this sealing portion is not resistant to impact, it is provided to protrude from the bottom surface of the container in order to increase the strength. In PTL 3, to increase the strength of the sealing portion even more, welded layers in a sealing portion are welded to be engaged with each other by a plurality of penetration portions.